Rust preventive oil composition



Patented June 1, 1954 UNITED STATES s TENT OFFICE RUST PREVENTIVE OILCOMPOSITION of Delaware N Drawing. Application July 28, 1951,

Serial No. 239,194

12 Claims.

The present invention relates to improved rust preventive oilcompositions and particularlyto oil compositions which contain new typesof additives to render them more useful as lubricants as Well as moreeffective in protecting ferrous metal surfaces against rust.

The rusting of ferrous metal machinery is always a serious problem,particularly in humid or tropical areas. It is often desirable that thelubricating oil used on machinery have rust preventive properties aboveand beyond those possessed by conventional lubricating oils. In the pastvarious compositions have been proposed to inhibit or reduce the rustingof ferrous metals. Some of these have involved metallic salts which,although not objectionable in many instances, may be seriouslyobjectionable where conditions of high temperature lubrication areencountered and where ash or other objectionable residues may be leftwhen the oil is consumed.

It is an object of the present invention to provide an effective rustinhibitor for lubricating oils used in internal combustion engines andthe like although the invention is not limited thereto. A still furtherobject is to develop a rust inhibiting oil additive which also improvesother properties of the oil, such as its pour point. It is a furtherobject of the invention to provide a substantially ash free rustinhibitor for the purposes described above, although here again thinvention is not necessarily limited to the ash free compositions. Forsome purposes metallic derivatives of the additives may be usedsuccessfully Where the oil is not consumed by burning or other hightemperature action, or where minor deposition of ash is not consideredobjectionable.

According to the present invention a nitrogencontaining complex acidsuch as an alkylene bisirnino aliphatic carboxylic acid, especially thedi-acid, is esterified or preferably only partially esterifled by asuitable alcohol. Such an acid is commercially available from the AlroseChemical Co. under the trade name Sequestrene AA, having the approximateformula Preferred alcohols for esterifying such acids are the aliphaticalcohols having between about 4 and 18 carbon atoms per molecule. Theseare used because they lend oil solubility to the esters but it will beunderstood that other alcohols, such as the cyclic or aromatic alcoholsmay be substituted in part.

While the partial esters which are oil soluble are preferred for rustinhibition, the fully esterified acids have some utility, especiallywhere pour point depression of the oil is desired. Where detergency isdesirable the esters may be fully or partly saponiiied with a suitablemetallic base such as a base of sodium, potassium, lithium, calcium,strontium, zinc or other metals.

Ordinarily the preferred products are the partial esters ofethylene-bis-imino diacetic acids, esterified with substantiallysaturated and unsubstituted aliphatic alcohols of the Cs to C20 chainlength range to the extent of one or two of the carboxyl or acid groups.

The esterifying alcohols, as noted above, are preferably of such chainlength as to render the esters, preferably partial esters where rustinhibition is the primary object, oil soluble, or at least reasonablysoluble in the oily medium. While alcohois of chain length as short as 4carbon atoms may have some solubility in certain oils it is preferred touse those having at least about 8 and preferably up to about 16 or 18carbon atoms in the aliphatic chain. A particularly effective andrelatively inexpensive alcohol is the mixed alcohol Widely sold underthe trade name of Lorol B which consists of a mixture of alcoholsderived from cocoanut oil and having 10 to 18 carbon atoms with anaverage chain length of about 13 carbon atoms. The OX0 alcohols of thesame general character and chain length may also be used. These, as iswell known, are branched chain saturated aliphatic alcohols, derivedfrom the carbon monoxide and hydrogen treatment of olefins.

Partial esters, particularly the monoand diesters of ethylene-bis-iminodiacetic acid, are potent rust inhibitors and can be used in proportionsas small as 0.001% of the Weight of the total oil composition.Ordinarily, proportions running from at least 0.605% up to about 0.2%are used. Concentrates may of course be prepared containing up to 10% ormore of the additive in the oil, to be diluted with additional oil asdesired.

The oily vehicle employed is normally a hydrocarbon lubricating oil,especially where the oil composition is intended to fulfill the dualpurpose of lubricant and rust preventive. In some cases, however, it maybe preferred to use synthetic or non-hydrocarbon oils as part or all ofthe lubricating oil, such as the esters of dibasic acids, other complexesters, polyglycols, ether glycols and the like which have recently comeinto use as lubricants and for related purposes. Also, lighterhydrocarbons than the usual lubricating oils may be used for somepurposes, although in 3 most cases they should be of viscosity at leastas great as that of ordinary kerosene. The mineral oils of ordinarylubricating grade are economical and highly satisfactory for mostpurposes.

While the diacetic acids have been particularly mentioned above, theacids may be derived from other low molecular weight carboxylic acidshaving from 1 to 4 carbon atoms in the aliphatic group. Ordinarily theacetic and propionic acid derivatives are preferred.

The invention will be further understood by referring to specificexamples which have been prepared and tested.

EXAIVIPLE I One mol of Lorol B alcohol (20'? g.) together with one-halfmol (1&6 g.) of ethylene bis-immodiacetic acid (Sequestrene AA) and 200cc. of toluene were placed in a three necked round bottom flask. Themixture was refluxed with stirring and nitrogen gas flowing and waterwas removed by means of a water trap. After refluxing at 128130 C., forone-half hour only 0.1 cc. of water came oif. Thereafter the reactioningredients and vessel were cooled and 3 g. of sulfosalicylic acid wasadded as a catalyst. The fiask was heated again until the contentsrefluxed at 130 C. The esterification was very slow and only one-halfcc. of water was removed after one and one-half hours of refluxing. 130-140 cc. of the toluene was next distilled off and the temperature roseto 190-200" C. After 7 hours the full theoretical amount of water wasrecovered. The product was filtered through a finely divided siliciousmaterial, Hyflo filter aid, and the remainder of the toluene wasdistilled ofi. The yield obtained was as follows:

Weight of material added:

The product contained 3.33% nitrogen.

A blend of the partial ester of Lorol B alcohol and the ethylenebis-iminodiacetic acid (Sequestrene AA) in an extracted Mid-Continentlubricating oil having a viscosity of 43 S. S. U. at 210 F. was testedfor rust inhibiting properties by the procedure of ASTM Rust TestD665-46T. This test method is intended to indicate the ability ofsteam-turbine oils, including those used for steam-turbine gears, to aidin preventing the rusting of ferrous parts should water become mixedwith the oil.

The result obtained is compared with the uninhibited oil in the tablethat follows:

Composition Results Pass.

Heavy Busting.

An additional example was prepared, making the tri ester first andthereafter preparing the barium salt as in the following:

EXAMPLE II Product A.-Trz' Lorol ester of Sequestvene AA A mixture of146 grams of Sequestrene AA, 300 grams of Lorol B alcohol, 1 gram ofsulfosalicylic acid and 500 cc. of xylene were charged to a 2 liter, 3necked flask equipped with stirrer, thermometer, and water trap. Themixture was heated for 5 days at a reaction temperature 155230 C. Duringthe heating, an additional 5 grams of sulfo-salicylic acid was added.33.5 cc. of water was removed. The xylene was then distilled off and theproduct filtered. The product was then heated for 2 hours at 160170 C.and blown with nitrogen in order to remove remaining xylene and lightends. The yield was 361.5 grams of ester. This product contained 3.31%nitrogen.

Product B.-Ba salt or in ester of Sequestrene AA 84 grams of Tri Lorolester of Sequestrene AA and 97 grams of a naphthenic lubricating oilhaving a viscosity of 40 S. S. U. at 210 F. were stirred and heated in abeaker at G. Then 3 drops of a silicone polymer foam depressant and 32grams of Ba(OI-I) 2.81-120 were slowly added to the ester. Product B wasthen blown with N2 at C. for one-half hour to remove remaining water andwas filtered through Hyflo diatornaceous earth filter aid. The yield was82.8 grams.

Product B contained 1.47% of barium by weight.

(a) Rust test (b) Detergency test.25 hour Lauson engine test Bearing Wt.Blend Varnish Loss, Gms./

Bearing 3 Wt. Percent Product B in Mineral Oil of 60 S. S. U. viscosityat 210 F 3. 50 0.085 Oil Alone 1. 4. 75 0. 092

In general, for the lubrication of engines and the like where detergencyis desirable the ester of this invention may either be saponified with asuitable metal base or conventional detergents may be added, or both.Thus, the product tested for detergency above was also tested with theaddition of calcium sulfonate and barium phenol sulfide, the latterbeing a combined anti-oxidant and detergent. These additional agentsimproved the performance of the oil composition as an engine lubricant,reducing both varnish and bearing weight loss in standard Lauson enginetests. Even for rust inhibiting purposes alone it may be desirable toadd minor proportions, preferably between 0.05 and 4.5% of an oilsoluble soap, preferably an oil soluble petroleum sulionate of calcium,barium, sodium, or potassium. These materials tend to promote rustresistance as well as to improve detergency but they should not be usedwhere emulsification is undesirable.

EXAMPLE IH 75 grams of Sequestrene AA mol) was combined with 207.5 grams(1 mol) of Lorol B alcohol and 300 cc. of toluene. These materials werecharged to a B-necked 1 liter flask equipped with a stirrer, athermometer, a water trap and a reflux condenser. On heating, thereaction went very slowly so the toluene was distilled off and replacedby xylene, adding grams of toluene sulfonic acid. The mixture wasrefluxed for 5 hours at 300 F., yielding 4.5 cc. of water. An additional10' gram of toluene sulfonic acid was added and the mixture refluxed for6 hours at 300 to 330 F. A total of 18.2- cc. of water was collected. Afurther 5 grams of toluene sulfonic acid was added and the mixturefurther refluxed for 5 hours at 330 F. The total water collected rose to21.4 cc. The resulting product was washed three times with a 5% sodiumcarbonate solution and three times with clear water until the water wasneutral to litmus.

The mixture was heated and blown with nitrogen overnight on a streambath to evaporate the water and left a yield of 234.5 grams. Theproduct, which appeared to be substantially fully esterified wasdesignated Lorol B ester of Sequestrene AA. It had a viscosity of 56.8S. S. U. at 210 F. and a nitrogen content of 2.41% as against 2.66%theoretical. It was tested for its pour depressing effect on variousmineral base lubricating oils of SAE 10 grade with the followingresults:

Pour point, F. Conventionally refined Pennsylvania, V. I.

100, vis. 45.3 S. S. U. at 210 F 5 Same, with 1% Example III 5 Solventextracted Mid-Continent neutral with added Bright stock--V. I. 103, vis.

46.1 S. S. U. at 210 F Same, with 1% Example III 5 Conventionallyrefined Mid-Continent neutral with added Bright stock, 95 V. I., vis.

43.6 S. *S. U. at 210 F +30 Same, with 1% Example III 0 It wil1 be notedthat the substantially fully esterifled Sequestrene AA" was an effectivepour point depressant in the Mid-Continent oils but not in thePennsylvania stock.

It will be understood that conventional antioxidants and other agentssuch as degras, waxes and the like may be added where a film type rustpreventive material is to be prepared. As indicated above various oilsand mixtures of oil may be used as will be obvious to those skilled inthe art.

What is claimed is:

1. An improved oil composition comprising a. major proportion of aliquid oily vehicle and a minor rust inhibiting proportion of at leastone oil-soluble material selected from the group which consists of thefull esters. partial esters and metal salts of partial esters ofethylene bisimino aliphatic carboxylic acid having 1 to 4 carbon atomsin the aliphatic group, the esterifying group being C3 to C18unsubstituted aliphatic alcohol.

2. A rust preventive composition comprising a major proportion of ahydrocarbon oil and a minor proportion of an oil-soluble metal salt ofat least a partially esterified ethylene bisimino di aliphaticcarboxylic acid having 1 to 4 carbon atoms in the aliphatic group, theesterifying group being Ca to C18 unsubstituted aliphatic alcohol.

3. A rust preventive composition comprising a major proportion of ahydrocarbon oil and a minor proportion of an oil-soluble at leastpartially esterified ethylene bis-imino diacetic acid, the esterifyinggroup being C8 to C18 unsubstituted aliphatic alcohol.

4. Composition according to claim 2 wherein said carboxylic acid isacetic acid.

5. Composition according to claim 2 wherein aid carboxylic acid ispropionic acid.

6. A rust preventive oil composition comprising a major proportion of aliquid oily vehicle of viscosity at least as great as kerosene andbetween 0.001 and 10% by weight based on the total composition, of a C8to C18 unsubstituted aliphatic alcohol ester of ethylene bis-iminodiacetic acid.

7. Composition according to claim 6 wherein the proportions of ester arebetween 0.005 and 0.2%.

8 Composition according to claim 6 wherein at least one but not morethan two acid groups are esterified.

9. Composition according to claim 6 wherein the esterifying aliphaticalcohol is a mixture of alcohols substantially within the C10 to C18range.

10. A rust inhibiting oil composition comprising a major proportion ofan oil of lubricating grade, a minor proportion of a Ca to C18unsubstituted aliphatic alcohol partial ester of ethylene bis-iminodiacetic acid, and a minor proportion of an oil-soluble metal base soapselected from the group consisting of oil soluble metal sulfonates andbarium phenol sulfide.

11. A rust inhibiting oil composition comprising a major proportion ofan oil of lubricating grade, a minor proportion of a mixed Clo-C18unsubstituted aliphatic alcohol partial ester of ethylene bis-iminodiacetic acid, and a minor proportion of an oil soluble metal basesulfonate.

12. A rust inhibiting composition consisting essentially of to 99.9% byWeight of mineral base lubricating oil, 0.05 to 4.5% oil-soluble metalbase petroleum sulfonate, and 0.005 to 1% of aliphatic alcohol esters ofethylene bis-imino diacetic acid having at least 8 and not more thanabout 18 carbon atoms in each alcohol group.

References Cited in the file of thi patent UNITED STATES PATENTS NumberName Date 2,412,945 Bersworth Dec. 24, 1946 2,428,353 Bersworth Oct. 7.1947 2,458,527 Oberight Jan. 11, 1949 2,524,219 Bersworth Oct. 3, 1950

12. A RUST INHIBITING COMPOSITION CONSISTING ESSENTIALLY OF 95 TO 99.9%BY WEIGHT OF MINERAL BASE LUBRICATING OIL, 0.05 TO 4.5% OIL-SOLUBLEMETAL BASE PETROLEUM SULFONATE, AND 0.005 TO 1% OF ALIPHATIC ALCOHOLESTERS OF ETHYLENE BIS-IMINO DIACETIC ACID HAVING AT LEAST 8 AND NOTMORE THAN ABOUT 18 CARBON ATOMS IN EACH ALCOHOL GROUP.